Hmm. I want to use 2 jpegs, 1 will be used as RGB the other as transparency. They are stored as a sprite sheet and I want to just use the same texture coordinates that are used in the sprite sheet for both images. Filter texture coords map to 0-1 so that won't work (alpha channel appears as entire sprite sheet instead of individual sprite). So using a shader instead how do I pass the alpha texture off as an additional uniform?